Electrical Noise Ideas

[cholder]

I have updated a Bridgeport Boss 5 with Gecko Drives (201X) and a single phase DC supply. I used a Bob Campbell breakout board with Mach3. Initally the steppers would growl and move if power was applied and Mach3 not running. I changed the Breakout board from M1 to N1 (ignore charge pump) and the system works. But still have occasional resets of the Mach3. I put a scope on the pins step and direction pins and I get a +/-1.5 volt ringing on the line at around 50usecs. I have grounded one end of the step and direction shields and have tried grounding the common on the DC supply. If I remove the fuses to the Gecko's, it stops. With a single Gecko connected it returns. It does not seem to get worse with all the Gecko's connected.

I'm looking for any ideas

TIA

[bobsch]

Have you checked the power supply output for noise? You may need a small (like .05 uF) cap across the output.

[cholder]

I assume you mean the stepper supply. The best I can tell it is clean. I will need to verify it. I have checked so many places I can't specifically recall checking it. I first thought it was coming from the VFD, but I cut the VFD off and it still exist. The power supply cap is slightly undersized but that will be remedied before the week is out. The ringing in the picture is on the step and direction screw on the breakout board, between there and the PC ground. I have not found that waveform on anything else I've checked. My scope does not have the range with my current probes to check the mains.

[mike_Kilroy]

do u have a good single point ground point? is ur pc case tied with a wire to it also? do u have the gecko motor leads in sep conduit or shielded cable tied at both ends to ground? did u try tying ur step/dir sheild to grond on both sides? did u try making an rf ground connection for the hi freq noise u r trying to get past by peeling back the pvc and wire wrapping the exposed shileds to earth grond points at the ends instead of a pig tale wire that is like a 1m ohm resistor at these freqs?

[cholder]

I found it, accidentally. I had run all the shield pigtails together to my star ground. I pulled the stepper wires out of the wire way and was going to separate them on my ground bar when I noticed the noise on the trace was less than 0.1 volt. I changed the jumper on the Bob Campbel breakout board to see if it made the motors growl and move and it did not. I moved the wires back into the wireway and machine went bananas again. I rerouted the stepper shield pigtails and it seems to be cured.